FIG. 6 is a plan view showing a plan structure of a prior art semiconductor device and FIG. 7 shows an equivalent circuit thereof. FIG. 8 is a diagram showing a prior art semiconductor device in a wafer. In these figures, reference numeral 100 designates a semiconductor wafer. A first and a second circuit (i.e., circuit elements) 2 and 3, respectively, are disposed on respective chip regions 10 of the semiconductor wafer 100. These circuits 2 and 3 are connected with each other by a transmission line 5. Herein, the first circuit 2 is a low noise amplifier and the second circuit 3 is a high power amplifier.
An input side transmission line 5a connected with the first circuit 2 is disposed at one end portion of the chip region 10. A microwave input side RF probe pad 1a connected with a grounding electrode at the rear side of wafer is disposed at the both sides of the transmission line 5a. An input side coplanar line 15a is constituted by the input side transmission line 5a and the input side pad 1a.
An output side transmission line 5b connected with the second circuit 3 and the microwave output side RF probe pad 1b are disposed at the other end portion of he chip region 10. An output side coplanar line 15b is constituted by the output side transmission line 5b and the output side RF probe pad 1b.
The chip regions 10 are divided into a plurality of chips by dicing after the wafer process is completed, thereby producing a plurality of semiconductor devices.
On-wafer microwave evaluation of such a semiconductor device is carried out as in the following.
The input side RF probe 50a is contacted with the input side coplanar line 15a and the output side RF probe 50b is contacted with the output side coplanar line 15b. A measurement current is supplied through the first and second circuits 2 and 3 via the probes 50a and 50b in this state to carry out an evaluation of microwave characteristics of both circuits 2 and 3.
In the prior art semiconductor device constructed as described above, the supply,. of a measurement current is carried out by contacting the RF probes 50a and 50b in contact with the input side and output side coplanar lines 15a and 15b, respectively, and therefore, only the characteristics of the whole of the first and second circuits 2 and 3 is obtained in the on-wafer evaluation. Therefore, when the characteristics of the semiconductor devices are bad, it was difficult to determine which of the first or second circuits 2 or 3 is faulty.
The above-described prior art semiconductor device has only two circuit elements, i.e., first and second circuits 2 and 3 for description. A large sized integrated circuit having a larger number of circuit elements has greater difficulty in the fault analysis, resulting in a serious problem.